The invention disclosed herein pertains to a manually operated bulb pump that has a variety of uses, but will be described in connection with creating a partial vacuum in a cylinder into which a male penis extends for inducing blood into the penis to thereby cause an erection.
Vacuum therapy is a widely used procedure for treating impotence. The procedure requires a man to dispose his penis in the open end of an otherwise closed tube or cylinder to which a vacuum pump is connected. The open end of the cylinder is pressed against the body circumjacent the penis base to effect a seal. Then the vacuum pump is operated to make the pressure in the cylinder negative relative to the atmosphere and relative to the body's blood pressure. As a result, the blood pressure in the body, being relatively higher than the pressure in the cylinder, causes the penis to become gorged with blood under pressure and expanded which is what occurs incidental to obtaining of a natural erection. When the erection is achieved, an elastic ring is slipped off the cylinder and onto the base of the penis to prevent backflow of venous blood and thereby maintain pressure in the penis and the erection.
The vacuum therapy procedure and existing equipment for practicing vacuum treatment are described and shown in U.S. Pat. No. 5,195,943 which is owned by the applicant of this application.
Pumps presently used for evacuating penile cylinders represent a substantial percentage of the production costs of the therapy system. A preexisting type of vacuum pump is shown in the patent cited above. The pump has a cylindrical body mounted coaxially to the penile cylinder to close the end opposite from the end of the cylinder into which the penis is inserted. A piston is manually recriprocable in the pump cylinder with an external handle and is coaxial with the pump and cylinder. A check valve is required in the pump to facilitate exhausting air from the cylinder and to prevent atmospheric air from leaking into the cylinder. The pump requires molding of several plastic parts and requires assembling of parts including a check valve which is labor intensive and expensive.
Besides high manufacturing cost and the use of movable parts, another disadvantage of this type of pump is that the user must reach out and away from the body with one hand to grasp the piston operating handle of the pump while holding the vacuum cylinder against the body tightly enough to avoid breaking the body seal too.
Another type of hand operated plastic vacuum pump that is widely used in connection with penile vacuum therapy is one that has been used for decades in chemical laboratories, for example, to create suction for accelerating filtering. This pump has a cylinder mounted to a pistol grip handle and a piston rod connected to a trigger lever that is squeezed repeatedly to reciprocate a piston until a pressure gauge on the vacuum cylinder registers a negative pressure of about 10 to 12 inches of mercury. This is the customary pressure or vacuum that is generally recommended for the treatment. The several separately molded parts of the pump plus the check valves and assembly time results in a rather costly pump. This type of pump is usually connected to the penile cylinder with flexible tubing.